An example of article transport facilities such as one described above is disclosed in JP Publication of Application No. 2011-116313 (Patent Document 1). In an article transport facility of Patent Document 1, an article transport vehicle includes a pair of travel portions, namely, a first travel portion and a second travel portion. Each portion of the pair of travel portions supports a transport vehicle main body such that each can be rotated independently about a corresponding vertical axis. The reason that each portion of the pair of travel portions supports the transport vehicle main body for independent rotation about a vertical axis is to allow the article transport vehicle to smoothly travel through curved portions of the travel path in addition to straight portions of the travel path.
In addition, in the article transport facility of Patent Document 1, a power-receiving portion of the article transport vehicle is supported by the transport vehicle main body at a location between the first travel portion and the second travel portion. Thus, with the power-receiving portion located between the first travel portion and the second travel portion, when the article transport vehicle travels through a curved portion, the power-receiving portion becomes displaced radially inward during the travel through the curved portion of the travel path, which reduces the efficiency with which the power-receiving portion receives power from electricity supply lines. This can cause the article transport vehicle to not receive sufficient electric power necessary for it to continue traveling.
Thus, in the conventional article transport facility described above, the power-receiving portion of the article transport vehicle is supported by the vehicle main body for sliding movement along a vehicle body lateral direction which is perpendicular in plan view to a vehicle body fore and aft direction which is the direction of travel of the article transport vehicle. The first travel portion and the power-receiving portion are operatively connected to each other by an operatively connecting mechanism such that the power-receiving portion slides radially outward when in the curved portion and in synchronization with the rotation of the first travel portion about its vertical axis.